When Arismendy Alcantara steps up to the plate in a big spot, he isn't nervous and he doesn't feel any extra pressure. He just goes up there looking to make contact.

Sunday afternoon was no different. Representing the go-ahead run, the Cubs' No. 6 prospect stepped into the box for Triple-A Iowa with two on and two outs in the bottom of the eighth inning. Keeping calm, he crushed a 1-1 offering from Neftali Feliz and launched it into the left-field grandstand to give the I-Cubs a 9-8 lead over the Round Rock Express.

"Just tried to do the best I can -- that's what I try to do. I don't worry about the situation of the game, I try to have a good at-bat," the second baseman said. "I just tried to hit it with contact. When I hit it, I knew it was gone."

The 22-year-old put his head down and jogged around the bases. He didn't see how far his home run went, but when he got back to the dugout, his teammates joked with him that it went 500 feet.

The lead stuck and Iowa held on in a game that had four lead changes, with each team collecting 11 hits.

"He put a whooping on it," I-Cubs manager Marty Pevey said of Alcantara's blast. "He got a pitch he could handle down and in. It was majestic, he really struck that ... wow."

Pevey watched the home run from a TV in the clubhouse as he was ejected in the third for arguing with home-plate umpire Spencer Flynn after Josh Vitters was thrown out of the game for tossing a bat after arguing a strikeout call.

But when the game ended and Iowa returned to the clubhouse, the manager grabbed Alcantara by the bicep, marveled at its strength and congratulated his 5-foot-10 second baseman.

"This kid, even though he's small, he has a lot of power," Pevey said. "He is a great player. He's got great tools. He's got speed, he has power, he can hit for average. … [But] he's going to need 300 or 400 more at-bats and learn how to stay back on the breaking ball."

The switch-hitter has been working in the cages to make contact with the breaking ball and said he is making little adjustments each day. But with top Cubs prospect Javier Baez hitting behind him in the order, Alcantara said he just thinks about getting on base and leaves the homers to the shortstop.

In the eighth, MLB.com's No. 77 overall prospect followed a long ball by Chicago's No. 11 prospect Villanueva to rally the I-Cubs to a series split with the Express.

"It was awesome. We fell behind early and we just scratched and clawed," the manager said. "Even though [starter Tsuyoshi] Wada gave up six runs, he gave us the innings we needed."

Wada yielded 10 hits over seven frames before handing the ball over to Marcus Hatley (1-0). The right-hander gave up two runs on a hit in one inning. Blake Parker hurled a perfect ninth for his team-leading eighth save.

Kelsie Heneghan is a contributor to MiLB.com. Follow her on Twitter @Kelsie_Heneghan. This story was not subject to the approval of the National Association of Professional Baseball Leagues or its clubs.